Fifteen-month drinking reductions in a randomized clinical trial of cognitive-behavioral and mindfulness-based treatments and a matched nontreatment-seeking community sample.

Objective: To examine drinking outcomes over time among two samples recruited and assessed using similar criteria, procedures, and measures: heavy drinkers who were not seeking treatment and treatment seekers.

Method: Heavy-drinking participants were recruited for a naturalistic study of the course of alcohol use in a nonhelp-seeking community sample (N = 190) and a randomized clinical trial (N = 110) of 2-4 sessions of motivational enhancement therapy followed by eight sessions of cognitive-behavioral or mindfulness-based treatment. Alcohol use was assessed with the Timeline Followback at baseline and 3-, 9-, and 15-month follow-ups. Percent heavy drinking days was the primary outcome variable; percent drinking days and drinks per drinking day were secondary outcome variables. Propensity score analysis was used to reduce potential effects of confounding, and latent growth curve model with maximum likelihood estimation was used to assess changes in drinking over time.

Results: Compared with the nonhelp-seeking community sample, the clinical sample showed greater reductions in frequency of heavy drinking and of any drinking over the 15 months of follow-up. There were no differences between treatment conditions on any outcome variable. The clinical and community samples both decreased their drinking over time with medium to large effect size reductions in the clinical sample and small effect size reductions in the community sample.

Conclusions: Both samples of heavy drinkers reduced their drinking over time, but receiving behavioral treatment was associated with more substantial decreases in drinking frequency and intensity, attaining levels comparable to or below that of a community sample. (PsycInfo Database Record (c) 2026 APA, all rights reserved).